Luo, A.C. and Xing, S. 2026. Time-delay Effects on Periodic Motions in a Periodically Forced, Time-Delayed, Hardening Duffing Oscillator. Journal of Vibration Testing and System Dynamics. 1, 1 (Aug. 2026), 73–91. DOI:https://doi.org/10.5890/JVTSD.2017.03.006.